Mobile jack



Nov. 6, 1951 J. D. THRESS MOBILE JACK 3 Sheets-Sheet 1 Filed 001;. 24, 1945 INVENTOR.

NOV. 6, 1951 THRESS 2,574,230

MOBILE JACK Filed Oct. 24, 1945 s Sheets-Sheet 2 Nov. 6, 1951 J. D. THRESS 2,574,230

MOBILE JACK Filed Oct. 24, 1945 3 SheetsS heet 3 INVENTOR.

Jhmas' Z'Zmsw 7%BY I i Zlbrnfys Patented Nov. 6, 1951 MOBILE JACK James D. Thress, Roanoke, Va., assignor to Charles M. OBoyle, Wilmington, Del.

Application October 24, 1945, Serial No. 624,195 I 7 Claims. (Cl. 254-1) The present invention relates to improvements in mobile jacks and more particularly resides in a self-contained motor and jack unit mounted upon a wheeled frame for convenience and easy movement from place to place.

More specifically the invention contemplates such a unit for a specific use, that is in and about railroad shops or in railroad repair yards where the jack is to be introduced beneath the end of the spring plank which projects beyond the side frames of the trucks of railroad freight and other cars.

The problem here is to use a squat jack, that is a jack of small height to admit of being received beneath this spring plank; yet a powerful jack and a sufficiently powerful motor or handpropelled arrangement to insure the quick and effective operation of such jack.

Wheeled jacks are known to the prior art in which the wheels are mounted relatively high up from the base at the side of the jack, permitting of the wheeling of the jack up to the work. However, on account of the extreme diagonal position assumed by the jack when the treads of its wheels are on the ground so as to permit of mobility of the jack, when arriving at the spring plank, the low position of the spring plank is such that the jack cannot be rotated from off its wheels on to its base to a position where the vertical axis of the ram of the jack will be in a position below the spring plank for the reason that the upper part of the jack head will strike the outer end of the spring plank and prevent the jack from being rotated down vertically into this final operative position beneath the spring plank.

Accordingly wheeled jacks made and used for the purpose are provided with side handles or side grips. The operation is to wheel the jack up as close as possible to the spring plank, then to upright the jack off its wheels and onto its base with the vertical line of the ram of the jack still outwardly beyond the end of the spring plank. A workman then seizes the jack in both hands by its side handles or grips and walks the jack into position beneath the spring plank. This walking consists in tilting the jack from side to side while pushing the elevated side forward so as to make the jack step from side edge to side edge gradually into position. This walking or stepping of the jack into position is one that requires time of skilled workers where time is a, valuable economic factor, particularly because repair procedures today in the railroads involve the cutting out of cars sustaininghot N boxes, the prompt removal of the car by shift engine to the repair yard where a. scientifically trained crew of highly skilled operators goes immediately to work on the car in the matter of removing, testing and if necessary replacing the brasses and otherwise restoringthe car to good running condition while the through freight train is held up until the repaired car is again coiipled into the train.

The problem involved in the use of prior art wheeled jacks is also the matter of convenience and ease of operation and the fact that the jack is, ormay be, unstable in its position even when finally setinplace. I It is a primary object of the present invention to remove the difiiculties above referred to and in fact to dispense entirely with one operation, that of walking or stepping the jack into final position, in that the self-contained wheeled unit of the present invention enables the jack during the actual wheeling operation to be pushed" into a final position beneath the spring plank where 'the ram of the jack is in condition to be elevated immediately after the movement of translation has ceased.

Another object of the invention is to so coordinate and relatively arrange the carrying frame,'

tiveness at the end of its period of transportation,-

the unit being so constructed and arranged that the weight of the car devolving upon the jack ram will act to relieve the wheels and their axle from any of the incumbent weight incident to jack operation which might otherwise bend the" wheel axle out of shape or bend the frame from. which all of the weight is automatically removed.

The invention has for its further object to pro-'- vide in a unit of the "ind described a slight preponderance of weight at the forward or jack end of the frame so that light pressure is required on' the handle end to elevate the jack for transporting movement, but the equilibrium of the'frame unit being such that when released the jack will automatically seek a position'of initial rest'from which it may lock'through a slight angle to a final'position of rest taking the weight and strain on the wheels and frame as soon as a predetermined weight value is placed on the ram of the jack.

With the foregoing and other'objects in View} the invention will be more fully described herein- Figure 2 is a top plan view of the improved v jack.

Figure 3 is a side elevation of the same. I I Figure 4 is a vertical section taken on the line 4-4 in Figure 2 and showing one form of jack that may be employed.

Figure 5 is a fragmentary side view of the jack in the static position and before the weight of the spring plank and the super-posed weights of the side frame and car are imposed on the Jack. r

' :Figure -6 is a similar view showing the positlon of the parts after such weights have been imposed on the jack.

Figure 7 is a fragmentary side view of a modifled form of the invention with direct drive from the motor to the jack through a universal joint coupling.

Figure 8 is a similar view showing also a direct shaft drive with a flanged coupling.

Referring more particularly to the drawings Hi designates generally a railway freight or other cal-having a truck of which H represents a side.

frame and I 2 the spring plank.

In accordance with the invention a jack [3 of any type, but of small vertical dimension so as to get beneath a projecting end of the spring plank I2, is mounted upon the forward end of a wheeled frame which may be constructed of any suitable parts, .in a simple form of the two substantially parallel and substantially horizontally extending side rails H and I5.

These side rails may have their edgewise dimensions disposed in the vertical in order to better assume the weight of the jack and other parts. The jack shell may be received directly between the forward ends of the two side rails l4 and I5 and welded or otherwise secured thereto. The jack l3 may be arranged to stand upon its own normal metallic base but is preferably aflixed upon a wooden or other base block l6 carried by the frame as by the use of legs I! which are welded to the side rails l4 and I5 and depend therefrom.

At their lower ends the legs are provided with out-turned perforated lugs l8 to receive the fastenings H which pass through the base block l6. Preferably the base block 16 is longer than the jack base in order to secure greater leverage as hereinafter described; and in such case the legs I1 will be set backwardly from. the middle transverse vertical plane of the jack to accord with the central transverse vertical plane of the base block I 8.

In some cases a gear box or reduction gear 28 is employed and in such instances the external case of the gear may be welded to the side rails I4. and I! or otherwise affixed in the frame. The input or motor shaft 22 may be secured to the input shaft of the gear box'as' by a coupling 2|.

A reversible air motor 23 or other type of motor or hand actuating device is carried by the rear portion of the frame and may be received between the side rails H and. Hi to which the motor may be -weldedor otherwise secured. The

frame I4, l5 has journaled therein the transverse axle or shaft 24 receiving the wheels 25 of relatively small diameter. The rear end of the frame has afiixed thereto by the brackets 21 a tubular handle shaft 26 carrying at its upper end a cross handle 28. One side of the cross handle accommodates a rotatable sleeve control 29 for air to the air motor 23, air being received from a suitable source through the "mr'hose-N which is coupled by an appropriate fitting 30 to' the control 29.

-'The other side of the cross handle 28 carries -a rotatable sleeve 32 for reversing the motor,

, reverse lever 35,. This reverse lever which may be in the form of a bell crank is fulcrumed at 36 to the-lower end of a bracket 31 carried by the tubular handle 26. A fork 38 on the dependent arm of the reverse lever loosely receives the handle of the crank for reversing the air motor. An air hose section 40 is coupled from the lower end of the hollow handle 26 to the intake of the motor 23.

A form of jack which has been employed with success, is shown in Figure'4. This jack is of the screw type and is made with an internally threaded ram sleeve adapted to be raised and lowered by the vertically disposed rotating screw 42 which receives its rotation through the bevel gear 43 to which it is affixed and the bevel pinion 44 which is coupled to the output shaft of the reduction gear.

The handle 26 may carry a stop 45 in the rotating path of the rock arm 33 to limit the angular movement of the reverse operating sleeve 32. The handles 29 and '32 may be externally knurled for convenience in gripping and rotating.

The air motor 23 may be suspendedin the frame pivotally upon Itrunnions 4B journaled to rotate in the upper end portions of upstanding metal supports 4'1 which are welded or otherwise secured to the sidebars or other parts of the frame. The transverse axis of the trunnions 46 will preferably pass approximately through the center of gravity of the air motor 23 whereby to supportsuch motor in a condition of neutral equilibrium whereby the motor 25.? may be rotated about the trunnions I! through a limited angle in either direction for the purpose of securing proper alignment of its drive shaft 22 with the input shaft of the gear reduction unit 20.

The jack I3 employed is preferably a journal jack of low height and the frame is low slung being secured to a low point upon the jack.

Contributing to this low position of the frame.

with respect to the ground line, the axle 24 is preferably journaled immediately below the side rails l4, l5 and the wheels 25 are small wheels and of comparatively small diameter. I

It will be noted that the axle of shaft 24, besides acting as journals for the supporting and transportation wheels 25, also constitutes a fulcrum on which the frame may be rocked in a fore and aft direction. Certain of the parts are to one side and certain of the other parts to the other side of this fulcrum or rocking axis. In the form shown and so far described the jack and the gear box 20 are forward of this transverse fulcrum 24 while the air motor 23, the handle 25v and the reverse gear all act as counterbalances to the rear side of the axis =24.

The parts are further correlated that the for- 5. ward portion of the frame will over-balance the portion to the rear of the fulcruni'24. In'other words the weight is preponderantly upon the front portion of the frame so that when the operator releases his downward pressure from the cross handles 28 the jack will descend with its base or base block [6 received upon the ground.

As shown in Figure the arrangement and construction is preferably such that at this atrest position the rear lower edge 48 of the jack base or base block I6 will first encounter the ground with the remainder of the bottom surface of the base or base block inclining upwardly and forwardly at a very small angle as indicated at 49 in Figure 5.

In the use of the device, the upstanding han-' dle shaft and supply pipe 26 rises so abruptly from the rear and normally overbalanced portion of the frame that the construction is favorable for the operator gripping the handle grips 29 and 32 to impose his weight downwardly through the handle shaft to the rear portion of the frame sufficient to lift the jack [3 and its base Hi from the position of rest upon the ground. The overbalance in weight need not be great so that slight pressure by the operator may lift the jack.

Moreover only a slight angular movement or turning movement of the frame about the axis 24 will suflice to clear the base Hi from the ground. It is only required that this base clear the ground by the smallest fraction of an inch because the ground over which the device is pushed in and about railway shops and repair yards is uniformly level. Therefore the jack base will only have to be lifted sufficiently to clear it of dragging upon the'ground, whereupon the carriage and all parts connected therewith are supported only upon the treads of the wheels 25, whereby the carriage is free to be moved forwards or backwards for the transportation of the jack to the point of work.

By the fact that the frame is made of the horizontal substantially straight bars [4, I5, the treads of the wheels 25 may rest upon the ground at the same time as the base fulcrum 48 rests upon the same ground line (see Fig.5). Also because of the fact that these straight frame members carry the jack l3 far forwards of the axis 24, only a slight turning movement in the,

frame will rotate the jack through a sufiiciently large arc to clear its base of the ground line. Moreover this arcuate lifting of the base will present an inclined bottom surface tending to ride over obstacles. This action is enhanced by the relative arrangement of the base and wheels as shown in Figure 5 in which the bottom sur-p the spring plank i2 and the handles released so that the jack and its base descend upon' the? edge fulcrum 48 at which time the treads of thewheels 25 are still'upon the'ground; There'-- In its slightly raised position the squate? 4 upon'air is'turned into the motor-by the manipulation of the sleeve 29, the direction of motor operation being controlled'by' the reverse sleeve 32 so that the motor 23 operates 'in' a proper direction to elevate the jack ram 4|. "As this ram engages beneath the spring plank l2 and assumes the weight of the same and of the springs and car, that weight will tend to rotate the jack about its base fulcrum 48 from the position of Figure 5 tothat of Figure 6 in which the plane of the bottom of the base block 16 descends uniformly upon I the surface of the ground. Thus thethrust of the weight through the vertical axis of the ram 4| is taken up di-' rectly by the jack base or by the jack and its block 16 and this rotary movement of the jack incident to the assumption of the weight will rock the frame in a direction to take all strains and stresses oil the wheels 25 if in fact not to lift the wheels slightly from the ground as exaggeratedly shown in Figure 6. p The angle 49 may be a very small one and the treads of the wheels 25 may never actually leave the ground. As the jack assumes the load, such load is transferred to the base It and is not at any time imposed upon the wheels 25. The rotation of the block l6 about the small angle 49 will cause the entire lower surface of the base Hi to be grounded on assumption of the weight, which action tends to further relieve the wheels 25 of the weight of the jack, the frame, the motor and other parts. Therefore while the wheels 25 assume the weight of all of these parts during transporting movement, in the actual jacking operation all weight is assumed by the jack and its base I 6 and actually such weight is thereupon transferred away from the wheels 25 by the rocking of the base l6 about the fulcrum 48.

Consequently the jack may be moved to its final operating position beneath the work by the same act of the operator employed in rolling the jack on its transporting movement; When the weight on the handles is released the jack is in its final position. There is no necessity to walk the jack into its final position. Moreover the jack automatically seeks a position, independently of any conscious effort on the part of the operator, where the weight of the load will actually operate to remove the stress and strain of that load from the frame, wheels and axle 24.

When the jack is lowered the handles are used to slightly tilt and then withdraw the jack from the work.

Compressed airlines are generally run underground through railway shops and repair yards and for this reason a reversible air motor 23 is on the journals Mi while the accompanying angular movement of the shaft 22 with respect to the jack shaft 50 is compensated for through the universal joint connection 5|.

- In Figure 8 a very similar arrangement shown in which the jack shaft 50" is connected; with the motor shaft 22 by a typica1'shaft'coup-" The reverse handle is fling 21" consisting of the flanges ."and :fixedly connecting the two shafts. .In this case themotor 23 'is carriedin' an offset axle.52 havin mam bblts for the Journals 53 for the wheels 25?.

One advantage of employing a 'base block it over the customary metal base of the external shell of the jack is that such block may be made considerably wider'and longer than the basejack thus presenting a greater surface area to the ground which is usually composed of a cinder bed. .The greater area will avoid the undue sinking of the jack into the bed-on imposition of the enormous loads encountered in connection with railway car work.

Another advantage from the use of the base block 16 is that its rear fulcrum edge 48 may be carried considerably backward of the rearmost part of the normal jack base, thus giving a greater opportunity for leverage and reducing the angle 49 which the bottom surface of the block l6 initially makes with the ground line. The reduction of this angle 49 to as low a value as practicable is important not-only in effectively relieving all strain from the frame and from the wheels 25, but also in keeping .as 'low as practicable the deviation of the ram axis from the vertical in the initial rest position of the device as shown in Figure 5. The angle of inclination of the jack axis to the vertical will be the same as the angle 49 and thus if the angle '49 is kept at a low 'value, the 'uprightingmovement of the jack incident to its assumption of the load will be a very small movement which is of course highly desirable. No particular purpose is subserved by lifting the treads of the wheels 25 off the ground. The purpose of the invention is subserved if merely the strain is lifted off such wheels and off the journalsof the axle 24 and off the side frame members l4 and I as such enormous loads as encounteredin railroad work would be apt to twist such frame members unless made unduly heavy and bulky and would tend to shear off the journals of the axle. Therefore the'angle 49 might be of the order of one degree or less and still secure at least in a measure the benefits of the invention.

It; will be noted that the jack is thus carried in a substantially upright position into the'work so that it need not be tilted to any extent in moving into the work. Its upper end or ram head thus easily clears the spring plankor'o'ther member to be lifted because it is inserted in place without requiring any substantial .upright-.

ing movement, it being remembered that the jack need only be lifted very slightly from the ground for the purposes of its transportation. In other words the jack may be trundled on the wheeled frame in this substantially upright position directly into place beneath the spring plankasan actual part of its transporting movement and the low value of the angle 49 will permit the jack to take up a substantially operative position as soon as the weight is relieved from the handlemem'ber.

It will also be noted that the jack is carried by the frame far forward of the wheels, that is of the pivotal axis on which the frame rocks and inasmuch as the frame members are :substantially in a horizontal direction the jack is carried on a line with the axle fulcrum 24, so that the vertical line of weight imposition is offset a considerable distance from the axle 24, thus making it practicable to have the treads of the wheels 25 and the base of the .jack rest upon the groundsimultaneously, as this relationof these parts contributes in great measure tolthat property o'fthe device which requires only azveryislight'lifting of the base-of the jackfrom the ground for the :wheels to assume the entire weight of the 'device for the purpose of itstransportation. This property of the device also distinguishes it from prior art wheeled jacks in that the disposition of the wheel axis with reference to the jack base is such as to require a rotation of thejack body through a considerable angular distance before either the treads of the wheels are brought into rolling contact with the ground in'one direction or where the jack base is uprighted in the other direction lifting the wheels high above the ground.

The-center'of gravity of the unit remains always forwardly of the axle 24. This center of gravity is never permitted to shift behind this axle 24 because the low slung frame would strike the ground at its rear part before that frame could be rotated sumciently about the axis 24 to bring the preponderantly weighted front part of the frame so high that the center of gravity would shift back of this axis 24. Therefore the jack can never topple backwards. Therefore when released the jack will always seek an upright position.

In the unit there are two systems of leverage. In the first instance the entire frame as a unit levers about the axis 24 in raising the jack of! the ground and later in permitting it to return to a state of rest on the ground. The balance of this system of leverage is one of unstable equilibrium. In thesecond instance, when weight is imposed on the jack the rear edge of the base block forms a fulcrum about which the unit rotates as a lever of the first order, this system of leverage being biased to a position with the wheels on the ground.

A satisfactory form of the invention has been built in the following dimensions:

Diameter of wheels 25 eight inches.

Distance from center of shaft 24 to the vertical center line of jack I3 where frame members are welded thereto, 13 inches.

Length of frame members I4, I5, 23 inches.

.Main distance of the lower edge of the frame from the ground line in the rest position of the jack, four and one-half inches.

.The value of the angle 49 can range from one to two and one-half degrees.

The jack is preferably not over ten inches high. The Joyce, Duff-Norton, Buda or any other journal jack may be used.

When the load is on the jack the wheels Il may clear the ground anywhere from one-half to one inch, which leaves the jack entirely straight under the load.

.It is obvious that various changes and modifications may be made in the details of construetion and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. In a mobile jack, a frame, a single transverse axle carried by an intermediate portion of the frame, two wheels fitted upon said axle for movement of the frame from place to place, said axle also constituting a fulcrum about which the frame may be rocked in a substantially vertical direction, a jack carried by the forward portion of said frame, a reversible motor carried by the rear portion of .said frame and coupled to drive said jack, a handle connected to the rear portion of said frame and having movable grips thereon for respectively controlling the forward and reverse gear of the motor and the introduction of active medium to said motor, the forward portion of the frame carrying said jack overbalancing the rear frame portion to cause said jack to automatically seek a position of rest when the weight of the operator is removed from said handle, said jack being so disposed in said frame that the rear portion of its base will first encounter the ground and form a fulcrum about which the base may rock to lift said wheels.

2. A mobile jack comprising a single axle, wheels mounted on said axle, a frame having members extending both forwardly and rearwardly from said wheels and supported intermediate its ends upon said axle for vertical turning movement, a motor supported upon the rearwardly extending frame members, a handle secured rigidly to the rear portion of the rearwardly extending frame members, and a jack coupled to be driven by said motor and carried by the forward portion of the forwardly extending frame members with its base substantially in the same plane with a tangent to the peripheries of said wheels whereby at least a rear area portion of the jack base may rest upon the ground simultaneously with contact of the wheels with the ground to enable the jack to be trundled in a direct line and in a substantially upright operative position directly beneath the work.

3. A mobile jack comprising a substantially straight horizontal frame, a single axle crosswise of said frame and supporting the frame at an intermediate portion thereof for vertical rocking movement with substantial forward and rear portions of the frame extending forwardly and rearwardly from said axle, two wheels on said axle for supporting the frame for rolling movement, a jack carried by the forward portion of said frame and having a planar base contacting with the ground at its rear area portion while the wheels also contact the ground whereby the jack assumes its upright position in the act of rolling the jack on the wheels into an operative position beneath the work, a motor coupled to drive said jack and mounted as a counterbalance upon the portion of the frame projecting rearwardly from the axle, and a handle secured to the rear portion of said frame.

4. A mobile jack comprising a frame, an axle on which the central portion of said frame is mounted for a vertical rocking movement with forward and rear portions of the frame extending forwardly and rearwardly of said axle, a jack having a base contacting the ground at its rear area portion simultaneously with the engagement of the peripheries of the wheels with the ground, the base of said jack forming with the ground line an angle of the order of one degree (1) a motor coupled to drive said jack and mounted as a counterbalance upon the rear portion of the frame and a handle rigidly connected to the rear portion of said frame. 7 v

5. A mobile jack as claimed in claim 4 characterized by the fact that said angle may be within the range from one degree to two and one-half degrees (1 to 2 6. A mobile jack comprising a substantially straight rigid horizontal frame, a single transverse axle supporting said frame at its intermediate portion for vertical rocking movement with forward and rearward end portions of the frame extending far forwardly and rearwardly of said axle, two wheels on said axle for the rolling movement of the frame, a jack carried at the outermost portion of the forward frame members having a. ground contacting planar base engaging at its rear area portion with the ground simultaneously with the contact of the peripheries of the wheels with the ground and in the rest position of the jack on the ground forming a. very small acute angle with the ground with its forward area portion diverging forwardly from the ground line, said base adapted to rotate through said angle on assumption of load by the jack to tend to rotate the frame and relieve the wheels of the incumbent weight of the jack, a motor coupled to drive the jack and mounted upon the rear portion of the frame rearwardly of the axle to counterweight the weight of the jack, and a handle rigidly connected to the rear portion of the frame.

7. A mobile jack as claimed in claim 6 in which said planar surface is formed upon a block on which the jack is supported, said block being of more extensive a surface than the bottom of the jack and extending an appreciable distance rearwardly beyond the bottom of the jack to produce a greater lever about which the rocking movement of the jack and frame may take place.

JAIHES D. THRESS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,349,101 Ripsch et a1. Aug. 10, 1920 1,461,820 Eek July 17, 1923 1,465,570 Arnold Aug. 21, 1923 1,838,715 Stewart et a1. Dec. 29, 1931 1,840,627 Hott Jan. 12, 1932 

